Well designed cardiovascular exercise programs can make exercise more effective, efficient, and even enjoyable. There are numerous cardiovascular exercise programs available to help people in their efforts to reach their health and fitness goals, including increased cardiovascular fitness, weight loss, or improved performance in endurance sports. Various factors are considered when developing a cardiovascular exercise program, such as the type of exercise to be performed, how much work will be done, and at what intensity training will be most effective. The type of exercise performed is primarily a matter of individual preference. The amount of work done (e.g., the length of each exercise session) should be reasonable, typically less than 60 minutes per day, to avoid overuse injuries and reduce the likelihood that the exerciser will stop exercising.
One of the more challenging aspects to developing an effective cardiovascular exercise program is determining the appropriate intensity for the training. In order to improve the function of the cardiovascular system, an individual must experience sufficient stress during exercise to stimulate adaptations. If training intensity is too low, sufficient overload is absent; however, if training intensity is too high, risk of overuse injury, cardiovascular events, and cessation of exercise are elevated.
A variety of methods have been employed to determine exercise intensity levels. One method uses percentages of an exerciser's maximum heart. The exerciser's maximum heart rate is calculated based on the exerciser's age, such as by subtracting the exerciser's age from 220. The exerciser then exercises at various intensity levels so that his or her heart rate is equal to certain percentages (e.g., between 60-85%) of the exerciser's maximum heart rate. One readily recognizable limitation of such a system is the lack of individualization of the system to specific exercisers. For instance, not all 40 year old men have a maximum heart rate of 180 beat per minute (i.e., 220-40). One 40 year old man may be quite fit, while another is just beginning a training programming Generic exercise programs, including age-predicted maximum heart rate programs, fail to account for each exerciser's unique fitness level.
Various exercise devices include the ability to monitor an exerciser's heart rate and adjust the operating parameters based on the detected heart rate. For instance, U.S. Pat. No. 7,713,171 discloses an exercise device that monitors a user's heart rate and adjusts the operating parameters to maintain the user's heart rate at a constant rate. Similarly, U.S. Pat. No. 7,857,731 discloses an exercise device that monitors a user's heart rate and adjusts the operating parameters if the user's heart rate is too high. Other exercise devices that monitor and/or adjust operating parameters based on the user's heart rate are disclosed in U.S. Pat. No. 4,998,725, U.S. Pat. No. 5,067,710, U.S. Pat. No. 5,512,025, U.S. Pat. No. 5,803,870, U.S. Pat. No. 5,879,270, U.S. Pat. No. 6,059,692, U.S. Pat. No. 6,193,631, U.S. Pat. No. 6,626,800, U.S. Pat. No. 6,749,537, U.S. Pat. No. 6,808,472, U.S. Pat. No. 7,575,536, U.S. Pat. No. 7,637,847, U.S. Pat. No. 7,575,536, U.S. Pat. No. 7,625,315, U.S. Pat. No. 7,510,509, U.S. Pat. No. 7,980,996, U.S. Pat. No. 6,921,351, U.S. Pat. No. 7,549,947, U.S. Pat. No. 6,312,363 U.S. Pat. No. 7,166,062, U.S. Pat. No. 7,060,006, U.S. Pat. No. 6,458,060, U.S. Pat. No. 6,997,852, U.S. Pat. No. 7,628,730, U.S. Pat. No. 7,789,800, U.S. Pat. No. 7,455,622, U.S. Pat. No. 7,645,213, and U.S. Pat. No. 7,981,000.